The K Prize - 100% reusable spaceplane to orbit and back

[G Addict]

Hm. Once I get into the lower atmosphere with the craft I posted, it goes into an uncontrollable tumble, I suspect because the canards behind the forward RCS tanks lift the nose more than the rear wings can lift the back of the plane. Any way to fix that without completely redesigning?

[Sean Mirrsen]

Hm. Once I get into the lower atmosphere with the craft I posted, it goes into an uncontrollable tumble, I suspect because the canards behind the forward RCS tanks lift the nose more than the rear wings can lift the back of the plane. Any way to fix that without completely redesigning?

If it were just canards, ASAS could have handled it. Something else is up. On my Albatruss MkIV-KS, I fixed the issue by removing a pair of swept wings from the nose of the craft and adding two pairs of such wings to the tail. You might also simply be lacking sufficient control surfaces, especially in the back.

By the way, does the concept of a cargo-delivering craft disqualify it from this challenge? The latest successful mission of the Albatruss MkIV-KS was putting a 4.5t cargo/fuel pod up into Kerbosynchronous orbit.

Repost of the mission log:

Skipping the whole egress/orbital insertion thing, because it\'s boring and I forgot to take screenshots for this mission. >_>

Payload released at something resembling KSO (I really should look into MechJeb)

Burn home complete:

Bit of a curiosity:

(not entirely close, but very nearby, in astronomical terms)

Returning to atmosphere:

Leaving atmosphere...

(gundamn reentry miscalculations)

Returning to atmosphere again:

Hopefully staying in the atmosphere this time:

(if reentry heat were simulated, I\'d be one big fireball right now)

Burning off rocket fuel for easier landing:

Final moments before touchdown:

Braking chutes out:

And we have landing!

Too bad the KSC is on the other side of the planet.

It\'s also recently managed to put the pod onto a Mun orbit, and very nearly hurtled out of Kerbin SOI by accident, but I\'ve yet to land that mission, and don\'t really have a lot of screenshots for it.

[G Addict]

I\'ve got more than enough wings to keep the rear end in the air - I have another version which is identical but has four less delta wings at the rear and can just about take off stably. They\'re not actually canards - they\'re the AV-whatever movable winglets. That make any difference? I just checked and I do need them to get it off the ground - even with them it only just gets the nose up in time to avoid going plop into the ocean, and tests while full have shown that it is able to land - even with about three times its intended landing mass. I\'ll try sticking more control surfaces on the rear, and replacing the forward winglets with proper canards. While I\'m at it I\'ll put the Aerospike engines on the decoupler hardpoints to stop them nicking the turbojets\' fuel on reentry. I think the separation between aeroplane fuel and rocket fuel will make this is thing fly a lot better. :

[Sean Mirrsen]

No, you do need canards. What you must absolutely not have is fixed wings toward the nose of the craft. Especially fixed wings not aligned with the center of mass. When you fly empty, the craft\'s nose is ridiculously light. If you have fixed wings near the nose, then whenever you deviate from the craft\'s flight path in atmosphere, those wings will start pulling you further off course. Canards will become useless once your angle of deviation exceeds their maximum tilt angle. What you need to do, perhaps, is remove a few of the flat panels up front, and change your canards to actual canards - those wing panels you have now are rather useless. Also be advised that inverted delta wings, like those you have on your tail, may actually provide negative lift. You also very, very definitely need more control surfaces on the back. More ailerons, more canard-like wings mounted sideways. Because nose canards become near useless if you\'re tumbling, you\'ll need as much drag and control power in the back as you can.

[G Addict]

Put some advanced canards on the front - now I don\'t have to roll down the hill to build enough speed to take off! ;D Put more control surfaces on the back but that made it too heavy to orbit and deorbit, added more rocket fuel, still too heavy. Took off some wheels and the small rocket (it runs out quickly and is basically just dead weight in the original design, no way to get it to use the rocket fuel and not the jet fuel in the new design), currently orbiting with a tank and a bit of fuel for each aerospike and two and a half tanks total for the turbojets. Looking promising...

EDIT: Gone too far the other way now. Where before it went crazy, it\'s now absolutely rock steady and refusing to come down, preferring to glide around at 50m/s. Currently circling with no power (have fuel, don\'t need it) to lose height above what I suspect is either a monolith or a tree - it\'s nighttime so I\'ve no idea whether I\'m going to have a safe landing or crash into a hill. :

EDIT 2: False alarm, it was a rock. And, despite it being nowhere near EITHER KSC due to a horrifically miscalculated aerobraking (too early by a rather large margin), I have successfully landed the soon-to-be-given-something-that-isn\'t-working-title KiG Spaceplane Mk2c! I\'m really happy I didn\'t have to make it look *too* utilitarian - I prefer my spacecraft to be pretty. 8)

[Sean Mirrsen]

Put some advanced canards on the front - now I don\'t have to roll down the hill to build enough speed to take off! ;D Put more control surfaces on the back but that made it too heavy to orbit and deorbit, added more rocket fuel, still too heavy. Took off some wheels and the small rocket (it runs out quickly and is basically just dead weight in the original design, no way to get it to use the rocket fuel and not the jet fuel in the new design), currently orbiting with a tank and a bit of fuel for each aerospike and two and a half tanks total for the turbojets. Looking promising...

EDIT: Gone too far the other way now. Where before it went crazy, it\'s now absolutely rock steady and refusing to come down, preferring to glide around at 50m/s. Currently circling with no power (have fuel, don\'t need it) to lose height above what I suspect is either a monolith or a tree - it\'s nighttime so I\'ve no idea whether I\'m going to have a safe landing or crash into a hill. :

EDIT 2: False alarm, it was a rock. And, despite it being nowhere near EITHER KSC due to a horrifically miscalculated aerobraking (too early by a rather large margin), I have successfully landed the soon-to-be-given-something-that-isn\'t-working-title KiG Spaceplane Mk2c! I\'m really happy I didn\'t have to make it look *too* utilitarian - I prefer my spacecraft to be pretty. 8)

Even though my own design will always look prettier to me, that is still a very nice-looking craft. I like the diamond-shape in the center, and the whole thing looks sufficiently futuristic. Very nice. Mine is positively Russian in comparison - a standard cargo plane airframe with extra engines and tanks strapped to it. But I still like it more. Because it\'s mine.

[G Addict]

Even though my own design will always look prettier to me, that is still a very nice-looking craft. I like the diamond-shape in the center, and the whole thing looks sufficiently futuristic. Very nice. Mine is positively Russian in comparison - a standard cargo plane airframe with extra engines and tanks strapped to it. But I still like it more. Because it\'s mine.

That\'s a standard cargo plane airframe?! That\'s the sort of crazy design I always wish I could get to work properly, which promptly falls apart or starts backflipping on launch. I love seeing those designs, but my inability to produce them means I have to settle for sleek. I actually preferred the look when it had the shorter fuel stacks on the aerospikes in the original design, and preferred the design before that which didn\'t have the RCS tanks at the nose even more, but this version looks acceptably slick. Now to see just how far I can push it...

EDIT: Are all those turbojets on the Albatruss actually necessary for flight? I find that the performance of my craft in the atmosphere didn\'t change much whether it had four, five or six engines in its various iterations, but those jets have a really large performance hit once I switch over to rocket propulsion. You\'ve probably already tried all the possible combinations, but I bet you could get away with removing one of the pairs of turbojets on those outer tricouplers. Or does that cause too much of a change in your centre of thrust and send you off balance?

[zekes]

Uuh......

Trying to overhaul Barrett 6 ver 2... No idea when it will be ready... See the stock community base 3.0 for its first flight, which will be sub-orbital to the alt-ksc.

Cheers! I\'ll post when we can say it won\'t explode or run out of fuel!

[Sean Mirrsen]

That\'s a standard cargo plane airframe?! That\'s the sort of crazy design I always wish I could get to work properly, which promptly falls apart or starts backflipping on launch. I love seeing those designs, but my inability to produce them means I have to settle for sleek. I actually preferred the look when it had the shorter fuel stacks on the aerospikes in the original design, and preferred the design before that which didn\'t have the RCS tanks at the nose even more, but this version looks acceptably slick. Now to see just how far I can push it...

EDIT: Are all those turbojets on the Albatruss actually necessary for flight? I find that the performance of my craft in the atmosphere didn\'t change much whether it had four, five or six engines in its various iterations, but those jets have a really large performance hit once I switch over to rocket propulsion. You\'ve probably already tried all the possible combinations, but I bet you could get away with removing one of the pairs of turbojets on those outer tricouplers. Or does that cause too much of a change in your centre of thrust and send you off balance?

It needs the turbojets to make an accelerating vertical ascent up to their operational ceiling. It also absolutely needs them to take off. Even if it didn\'t need them for takeoff, being able to fly vertically upwards on kerosene is a reward in itself. Instead of burning rocket fuel all the way up, you only start burning it at 10km in the air, and already doing 200m/s. That\'s why I could get away with just sixteen rocket fuel tanks, instead of twenty-six as on Albatruss MkII, which has to burn it from takeoff. Even if it\'s just a minute of extra burn time, six LFEs will use up five full tanks of fuel during that minute, that\'s five tanks extra you\'ll have to pack along, and then lug around with you.

If I remember right offhand, the takeoff mass of my craft is something around 110 tons. Nine turbojets give a total theoretical thrust of 1350, so if I remove two engines I won\'t be able to efficiently ascend. If I use two LFEs to compensate, that\'s almost two tanks of fuel for ascent. So all in all, having the extra engines is better, even if you don\'t need them all the time.

[_Aramchek_]

Hello, here is my first successful spaceplane, it fits all the requirements so I thought I\'d post it.

It\'s one stage, very stable in level or vertical flight, and it is easily capable of hitting 70k meters and returning to Kerbin. Although I have simply put them in to orbit at this point, during testing.

This design works great as a simple airplane as well, just switch to jet engines.

[boolybooly]

Thanks for your mission reports _Aramcheck_ and Sean Mirrsen, both very interesting craft but by your own testimonies the challenge has not been strictly completed in each case, so I put you both on the gate crashers list to acknowledge your worthwhile contributions to the thread. Will adjust when you confirm a completed challenge flight as was the case for G Addict.

Grats on getting your craft to fly G addict and welcome to the official guest list (roll of honour). Did you get my 'blow out in damper three' reference in the now removed gate crasher comment? That was pilot chat from the title sequence to 'The 6 Million Dollar Man'. FYI

Thanks geb, nice ship, worthy Mün landing and return. You are on the guest list and have earned an ***Astrokerbal Distinction***.

[G Addict]

I realised the \'blow out in damper three\' was a reference, but couldn\'t for the life of me remember where it was from. Either way, it\'s a suitably amusing phrase on its own, though I\'d have thought something like \'bit off more than they could chew\' would be more appropriate to my stupidity. After a bit more fiddling, I\'ve found this craft has some trouble getting much further than a 75x75km orbit and returning, so have gone about pulling as many bits off as possible to eke out as much performance as possible. It\'s wonderful when flown as a jet, but a terrible rocket.

[_Aramchek_]

I\'ll be uploading a video later fitting all parameters, I\'d have it now but I had a slightly rough landing due to bad planning and bad fuel management.

The rocket engines broke off on a slightly rough landing, the rest of the craft was perfectly intact.

That said, the plane very easily accomplishes the mission goals, I circled Kerbin once in an elliptical orbit, the highest point was 145,000+meters, top speed was 2,7000+ m/s.

No mods used whatsoever, in terms of build or guidance.

I\'m still balancing the weight vs. fuel vs. lift for gliding back to the ground.

[_Aramchek_]

Mission accomplished, unfortunately I have to find an alternative to youtube to upload the video as they will not allow me to upload a video over 15 minutes long without giving them my cell phone number.

[togfox]

The overwhelming majority of these craft have a front/nose wing or forward canard. The only craft without front wings are really small. It seems large craft MUST have front wings. Reasons from you experts? Are the parts not quite right or is the atmosphere not what we would expect?

[boolybooly]

togfox IMHO - Its to do with lift relative to center of mass in the Unity simulation. Weight distribution changes as fuel is used, initially the center of mass is nearer the middle and engines are typically at the back. At the end of the flight the center of mass moves back towards the engines, if you have too much lift too far forwards at this point in the flight the craft flips back to front. So you need to keep the wings over the engines, but then you need a little extra lift / attitude control in front of the center of mass on lift off to get the nose up because the wings are behind the center of mass at that point, so the mass tends to change the attitude of the craft so it points towards the ground. You can make craft with engines and wings in the middle and they dont tend to need canards if they have a good tail plane for attitude control. IMHO

Aramcheck, grats & cool, will wait till I have seen the vid so I can see which accomplishments to include.

[Sean Mirrsen]

The overwhelming majority of these craft have a front/nose wing or forward canard. The only craft without front wings are really small. It seems large craft MUST have front wings. Reasons from you experts? Are the parts not quite right or is the atmosphere not what we would expect?

Large SSTO craft are usually quite heavy on the hind end, and quite heavy in general, requiring a decent angle of attack to lift off. Unless the rear landing gear are very close to the center of mass and are raised sufficiently to allow the engines to safely clear the ground on takeoff or landing, canards are absolutely required to lift the craft\'s nose up. The only alternative is a long reinforced swallowtail behind the craft, to apply a similar amount of leverage. My Albatruss is heavy enough to warrant using both. I could actually attempt to get rid of them, putting some extra control surfaces on the tail. Though I expect it won\'t do any wonders for maneuverability.

And I might try and complete a run of the Albatruss MkIV with the pod attached. It\'s dead weight anyway, the fuel in it is never used, and the craft actually handles a lot better when it\'s still present.

[_Aramchek_]

I just broke the video in to two pieces for now.

I can upload the whole later somewhere else.

[Saaur]

Cascade Aerospace is proud to bring you Simplicity III! A cute little 14 ton (takeoff weight) single engine fixed wing orbital vehicle.

Please note I didn\'t complete a full orbit or attempt to land back at KSC. My piloting skills are not legendary (or perhaps just legendarily bad) and I needed the broad east-west expanse of Keurasia to make sure I didn\'t drop my guys in the drink (again) but this craft is fully capable of 100%^ reusable flight if piloted by someone else.

Ready for night-time takeoff

Ignition

Liftoff

Beautiful Sunrise during ascent

In orbit. Traditional 'upside-down' orientation for optimal antenna angle.

Deorbit burn complete, reoriented for aerodynamic landing.

500m, gear deployed

Descent speed nominal. Might not crash this time.

Touchdown and full stop! Please remain seated with your seatbelt securely fastened until we have taxied to the runway (there\'s one on this continent, right?)

Mission Log

[boolybooly]

Good luck with your next attempt then Sean Mirrsen. I noticed you are already on the guest list due to the previous mission you did.

Thanks for posting the videos _Aramcheck_, well done on your successful flight with your new design, consider yourself on the guest list. I hope I got the craft name right, hard to read the vid, FFu3 ?

Saaur and Cascade Aerospace, that is a neat little ship, grats on completing the mission successfully and efficiently, thanks for your illustrated report. Your invitation to the Dog & Booster backstage event is confirmed.

Inspired by some of the elegant craft on display in this thread and with an eye on the Orion III spaceplane from 2001 A Space Odyssey, I have been working on another design and taking it for a spin to make rendezvous with a space station. Screenies below. I am thinking about making a movie but my arm still hasnt recovered from the RSI I encurred on my last editing spree !

[Phoenix Aerospace]

I\'m not sure this qualifies, as it uses modded parts (specifically the Kosmos pack and probodobodyne), but here\'s my Swift Mk.1. It\'s capable of a 200 Km. orbit with fuel to spare, and it\'s powered entirely by RCS to boot!

[colmo]

Did the challenge, realised my plane was not legit, started again, realised it STILL wasn\'t legit, third time\'s the charm:

I think I only qualify for the landing on terrain prize - I haven\'t yet figured out how to de-orbit a space-plane so I land on the same continent I\'m aiming for...

[rustymcclintock]

Woot! I have an SSTO spaceplane in orbit at 230km, I\'ll land at the KSC and upload the pics, watch this post!

Update: Aircraft failed to return to Kerbin, the weight distribution was such that the engine flew through the airframe and the craft disintegrated, I have another more stable plane but I need to get out in this sun, it\'s been cold for so long here.

lmao..hey everyone watch me...

[shhhilent1]

Did the challenge, realised my plane was not legit, started again, realised it STILL wasn\'t legit, third time\'s the charm:

I think I only qualify for the landing on terrain prize - I haven\'t yet figured out how to de-orbit a space-plane so I land on the same continent I\'m aiming for...

retro burn when you get about a continet away, and make sure that your orbit ends (crashes into kerbin) AHEAD of your target. dont worry, the re-entry drag will slow you down.

[boolybooly]

A manoevurable looking spaceplane there colmo and congratulations on bringing her back in one piece, consider yourself on the official guest list and thanks for all the screenies linked.

Like shhhilent 1 said, reentry is about slowing down so the obit line in map intersects with the drop zone, plus a bit extra to allow for drag and also for how Kerbin rotates while you are getting there.

Thanks for the screenies Phoenix Aerospace, amazing that you got to orbit with RCS but as you say the RCS tanks at least look like mods and not sure about the nozzles so I have put you down for a humorous citation as a gatecrasher, hope you are amused